A thin film technology has been widely utilized for the purpose of the reduction in device sizes and the increase in device performances. There are various film formation methods used for the manufacture of the thin film. Examples are a deposition method, sputtering, ion plating, CVD, and laser ablation. These methods are used depending on the purpose. The deposition method comparatively excels in productivity. In the deposition method, resistance heating, induction heating, electron beam heating, or the like is used as a method of applying energy for heating and evaporating a film formation material.
One problem of the deposition method is the use efficiency of the film formation material. To be specific, from the standpoint of manufacturing cost, it is important to efficiently precipitate and deposit the evaporated, scattering film formation material on a substrate. To solve this problem, it is effective to use a nozzle-type evaporation source. In the case of using the nozzle-type evaporation source, the film formation material can be emitted from only an opening surface of a nozzle. Therefore, the scattering of the film formation material can be limited. By locating the opening surface and the substrate close to each other, the film formation material can further efficiently adhere to the substrate.
PTL 1 discloses that: in a device configured to form a synthetic resin coating film, open-close devices and evacuating devices are respectively provided for two raw material monomer evaporation source nozzles, and each of inner portions of evaporation source containers is maintained at a constant degree of vacuum regardless of the open or close state of the open-close devices. PTL 1 describes that with the above configuration, the synthetic resin coating films of the same quality are reproducibly, stably formed on the substrates.
PTL 2 discloses that in a method of manufacturing a negative electrode for a nonaqueous electrolyte secondary battery, lithium is supplied by a dry film formation method to a plurality of columnar bodies projecting from the surface of a current collector.
In the deposition method, in a preparatory stage before starting the film formation, the film formation material needs to be adjusted to obtain vapor pressure necessary for the film formation by, for example, heating the film formation material. However, if the film formation material evaporates during the heating, the material loss occurs. Preventing the material loss is important from the standpoint of manufacturing cost.
PTL 3 discloses a method of performing deposition using an organic thin film material. According to PTL 3, in a state where the organic thin film material is accommodated in an evaporation source container, a vacuum pump is activated to evacuate the evaporation source container, the organic thin film material is increased in temperature, and degassing is performed. Then, an inert gas for suppressing the evaporation is introduced to the evaporation source container, and the organic thin film material is further increased in temperature. After the organic thin film material reaches an evaporation temperature in vacuum, the evaporation source container is evacuated by the vacuum pump. Thus, the vapor of the organic thin film material is generated. Then, an evaporation source shutter and substrate shutter provided above an emission opening of the evaporation source container are sequentially opened, and the formation of an organic thin film on the surface of a film formation target object provided in a vacuum chamber is started. According to the method described in PTL 3, since the generation of the vapor of the organic thin film material is suppressed under an inert gas atmosphere, the organic thin film material can be effectively utilized. PTL3 also describes that since the inert gas serves as a heat medium, the temperature increase rate is high, and thermal uniformity is good.